BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	cntrycode,
	count(*) as numcust,
	sum(c_acctbal) as totacctbal
from
	(
		select
			substr(c_phone, 1, 2) as cntrycode,
			c_acctbal
		from
			customer
		where
			substr(c_phone, 1, 2) in
				('22', '14', '29', '10', '20', '25', '26')
			and c_acctbal > (
				select
					avg(c_acctbal)
				from
					customer
				where
					c_acctbal > 0.00
					and substr(c_phone, 1, 2) in
						('22', '14', '29', '10', '20', '25', '26')
			)
			and not exists (
				select
					*
				from
					orders
				where
					o_custkey = c_custkey
			)
	) as vip
group by
	cntrycode
order by
	cntrycode;
                                                                             QUERY PLAN                                                                             
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Sort  (cost=694010.35..694010.36 rows=3 width=20) (actual time=12393.688..12393.688 rows=7 loops=1)
   Sort Key: (substr((customer.c_phone)::text, 1, 2))
   Sort Method: quicksort  Memory: 25kB
   Buffers: shared hit=237261 read=89589 written=4
   InitPlan 1 (returns $0)
     ->  Aggregate  (cost=52842.74..52842.75 rows=1 width=4) (actual time=759.901..759.901 rows=1 loops=1)
           Buffers: shared hit=9 read=36331
           ->  Bitmap Heap Scan on customer customer_1  (cost=6633.65..51892.21 rows=380212 width=4) (actual time=92.527..689.036 rows=381176 loops=1)
                 Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,14,29,10,20,25,26}'::text[])) AND (c_acctbal > 0::double precision))
                 Heap Blocks: exact=35278
                 Buffers: shared hit=9 read=36331
                 ->  Bitmap Index Scan on customer_c_phone_idx_c_acctbal  (cost=0.00..6538.59 rows=380212 width=0) (actual time=83.629..83.629 rows=381176 loops=1)
                       Index Cond: (substr((c_phone)::text, 1, 2) = ANY ('{22,14,29,10,20,25,26}'::text[]))
                       Buffers: shared hit=7 read=1055
   ->  HashAggregate  (cost=641167.53..641167.58 rows=3 width=20) (actual time=12393.634..12393.636 rows=7 loops=1)
         Group Key: substr((customer.c_phone)::text, 1, 2)
         Buffers: shared hit=237258 read=89589 written=4
         ->  Hash Anti Join  (cost=597214.53..640729.11 rows=58456 width=20) (actual time=11622.186..12368.895 rows=63609 loops=1)
               Hash Cond: (customer.c_custkey = orders.o_custkey)
               Buffers: shared hit=237258 read=89589 written=4
               ->  Bitmap Heap Scan on customer  (cost=2904.69..41844.10 rows=139482 width=24) (actual time=823.606..1357.475 rows=190709 loops=1)
                     Recheck Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,14,29,10,20,25,26}'::text[])) AND (c_acctbal > $0))
                     Heap Blocks: exact=35170
                     Buffers: shared hit=20 read=72037
                     ->  Bitmap Index Scan on customer_c_phone_idx  (cost=0.00..2869.82 rows=139482 width=0) (actual time=814.638..814.638 rows=190709 loops=1)
                           Index Cond: ((substr((c_phone)::text, 1, 2) = ANY ('{22,14,29,10,20,25,26}'::text[])) AND (c_acctbal > $0))
                           Buffers: shared hit=18 read=36869
               ->  Hash  (cost=405686.04..405686.04 rows=15089904 width=4) (actual time=10592.291..10592.291 rows=15015000 loops=1)
                     Buckets: 16777216  Batches: 1  Memory Usage: 658944kB
                     Buffers: shared hit=237235 read=17552 written=4
                     ->  Seq Scan on orders  (cost=0.00..405686.04 rows=15089904 width=4) (actual time=0.018..4245.401 rows=15015000 loops=1)
                           Buffers: shared hit=237235 read=17552 written=4
 Planning time: 2.953 ms
 Execution time: 12428.309 ms
(34 rows)

COMMIT;
COMMIT